Since then, Steep Hill has added high-performance liquid chromotography to test edibles for potency. The club also cultures for mold, and since 2010, tests for popular types the top five most common pesticide groups used on pot.

According to a December 2010 white paper, Steep Hill has found neurotoxic pesticide residues on some cannabis, and about five percent of medical weed supplies exceed USDA guidelines for microorganisms in agriculture products. Steep Hill tests run $120 per sample.

The lab still has scientific validity problems. It's illegal to possess pot under federal law. Steep Hill''s methodology has never appeared in a peer-reviewed journal. They lack accreditation, but seek ISO 17025 and ELA certification in 2011. They won't disclose their methodology, or the chemist who wrote and tested it.

“Validations in cannabis come in the form of self-validations,” said co-founder David Lampach, a self-taught chemistry enthusiast and grower. However, Steep Hill does perform inter-lab validations with other pot labs. “Any lab that wants to do that with us, we're open for peer review.”